ATI 3D Rage Pro adaptor no good for Sims 2

My daughter has been given Sims 2 for Christmas, but her PC has an ATI 3D Rage Pro which is not good enough to run the game.
Can anyone suggest the cheapest alternative that will do the job. She probably won't be keeping the computer for a whole lot longer, so i don't want to buy an all-singing all-dancing card